[SRU][Q][PATCH 2/2] drm/i915/dp_mst: Disable Panel Replay

[AceLan Kao]

From: Imre Deak <imre.deak at intel.com>

BugLink: https://bugs.launchpad.net/bugs/2136979

Disable Panel Replay on MST links until it's properly implemented. For
instance the required VSC SDP is not programmed on MST and FEC is not
enabled if Panel Replay is enabled.

Fixes: 3257e55d3ea7 ("drm/i915/panelreplay: enable/disable panel replay")
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/15174
Cc: Jouni Högander <jouni.hogander at intel.com>
Cc: Animesh Manna <animesh.manna at intel.com>
Cc: stable at vger.kernel.org # v6.8+
Reviewed-by: Jouni Högander <jouni.hogander at intel.com>
Signed-off-by: Imre Deak <imre.deak at intel.com>
Link: https://patch.msgid.link/20251107124141.911895-1-imre.deak@intel.com
(cherry picked from commit e109f644b871df8440c886a69cdce971ed533088)
Signed-off-by: Chia-Lin Kao (AceLan) <acelan.kao at canonical.com>
---
 drivers/gpu/drm/i915/display/intel_psr.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index ba80f8b36cd78..179b7d27eb4c4 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -602,6 +602,10 @@ static void _panel_replay_init_dpcd(struct intel_dp *intel_dp)
 	struct intel_display *display = to_intel_display(intel_dp);
 	int ret;
 
+	/* TODO: Enable Panel Replay on MST once it's properly implemented. */
+	if (intel_dp->mst_detect == DRM_DP_MST)
+		return;
+
 	ret = drm_dp_dpcd_read_data(&intel_dp->aux, DP_PANEL_REPLAY_CAP_SUPPORT,
 				    &intel_dp->pr_dpcd, sizeof(intel_dp->pr_dpcd));
 	if (ret < 0)
-- 
2.43.0